Motor construction



I12, 1958 R. EV. ZWAYER 2,846,984

MOTOR CONSTRUCTION Filed Nov. 9, 1954 2 Sheets-Sheet l INVENTOR. ROBERTE.ZWAYER ATTORNEYS Aug. 12,

Filed Nov.

R. E. ZWAYER 2,846,984

MOTOR CONSTRUCTION 9, 1954 '2 She'ets-Sheet 2 my air}; 55 g; $z 4000 7TORQUE- lb. ft.

55 CUBIC FT 45 35 PER MIN.

7 TORQUE- lb. f1.

JNVENTOR.

ROBERT E. ZWAYER JM W ATTORNEYS United States Patent y 2,846,984} Mornicmssrnu rlom Ro w y nBr qi 1 .1 a si n n A quipment Corporation,-Bryan, Ohio, a corporation ofyOhi'o pp ic t o N v mb r g l54, SeriaLNo.467, 17

s claiip cl' 1 2 1--;--s4 I This invention relates generally to a motorconstrucmm, and 'morepar'ticularly:to a reyersible pneumatic.

motor of, the rotary -,va'ne type.

The motor construction of the ,present invention may be p'l is hea iWiFE$ f. he. paema si for moyingload's fromone height; level toanother., Such,

hoisting devices generally utilize a'reyersible type motor havingsuitable controls for changing both the speed and the direction of driving rotatipn. v During the practical operation of such hoists, themotor is. not needed to effect lowering of the load, and ;lowering. maybeeffectedby.

gravity force,alone,-lregulated. by brake means. It will be apparentfrpm tl e pres'ent inyention that if some of the potential on the-reverse side oi the motor can be, transferred to th e forwardside,while retaining sufiicient motor power 'in reverse operation to drivean, empty Q 't chain d w wardlyat ar asanab spee t em can serve thehoist with substantially greater cfficiency,

er y, abl nslt fl h st o; and e: eav qa at sh flspee sl,

, It s P imaIY biQ L QI iQ sqntg ye ion h fore, ,tqr e numa 9 q q ttion, f e. ry, v n pe hav bs nt a gr aaedrow in the forward or liftingdirection of driving operation as compared to the performance of priorart constructions, wherein the gain in; power ;in the forward or liftingdirection isfigreater than tbe loss in power in the reverse or lowering}direction,;

It is another object to proyide a reversible pneumatic motor of tha-rotary ivane type havinga compressed air inlet and a;pair ;of portscomprising-primary- -and secondary exhausts, wherein the primaryexhaust; isparticularly positioned in unbalanced relationbetween;theinlet and the secondary exhaust,

It is a further. object to, provide, a motor, construction. 2 he. yp fist d, ,whsx iaa ha ma hau is unba nwdataaan l o iupt about Off, n e

he ndfl 'ther, i qta ny ew my nv nt on consists in the construction,arrangement and c'ornbinaus parts of my motor. construction whereby theobjects contemplated are obtained as herea e marefu y et o th; po n outin m m tion of}, the va and illustrated in Ithe accompanying drawing,wherein; Figure l is a side eleyational view, partly inper- Pt eL9winsap eumati; 9$? e e j c type nfw ish t heuma c; moto i on t t q bthe p s inv nt on e .ze L

Figure 2 is a fragmentary vertical sectional view, of:

hw nst ust qn; tE s r i na enla ed a a h ng e li bi. on ngdf. h uanei mic moto Figure 3 is 'ano e e'tional view, on a further ena ed scale, takn tantia y. nd a 1;. the l ne 3, qaF 't te 22, 1 in t e Pa lar locationQ -Ih eria l r sum t qe P tted a a t mane. a h forward and reverserotation of a pneumatic m otor conru iqn orr n n IQ i u e 3 whe e n Pr yexhaust isparticularly located in oiIset relation at, an

angle of about 28 frornxcnter;

Figure] is another plgt sirhilar to,' Figure 6,; for a Qw wQn rw -Q sqaeI12aa i Jq=E g w er in-v the primary exhaust, is particularly'locatedtin ofiset relaw tion at an angle of about .13? from eenterttand,

Figure: 8 is another plot similar; to, Figures 6 and. 7, for a motor,construction correspondingto Figure 5, ,wh erein the primaryexhaust isin balanced,arrangement in the.

manner of the prior art Referring nowmoreparticularly ,to Figures l to 3of the drawing, I have used the I reference. numeral 10 to indicate the.housing ofia typical hoisting device in which the motor,construction,of. the present inventi0n..may be employed Theihousing fl tl lis of,..holl ow formv andlen closes a stator 12 havinglalcyl indricaljbore.fthereindef fining a cylindrical internal surface surroundingtarotor 14 ,rotatably mounted, on al motorlshaftelbg The rotor:14,,isformed1with a plurality pf. rad-iallyaextending vane slots 18;,which serve, t-oreceiv'ei a corresponding plurality of radially;outwardly wslidable vanes :20} The yanes moveioutwardlyin theslots lsrin response to centrifugal forces when the' rotor. 14 ;is .driven,\ andserve to effect continuousgcontacting.engagerne ntwith the internalsurface formed by the stator 12.

As .be s t.,seen in Figure 3 .otthe drawingtthe longitudinal axis of thebore of, the stator. 12; is eccentrically disposedjrelative to ,thercoincident axes of the housing ltl and the rotor, l l inr theconventional manner .of pneumatic:motor constructions A -lower portionof the outer cylindrical surface thelrotor ld contactingly en- Flexibl eelements- 36 and-3 8;are suspendedsfrom the,

ends Qot a control lever v40-, andiserve to permit manual rotation ofia.,rock;shaft- 42 for. motor-forward or load.

up operation and motor-reverse or load down opera tion, respectively.The rock shaft 42' effects control actuation-of a suitableairiregulating .valve and brake, not

illustrated :in detail hereinbut of the general type shown and describedin co-pending Zwayer application Serial No. 490,968,'filed February 28,1955,'having a common assignee withthe present invention.

As best seen in'Figure, 2 of the drawing the motor shaft 16 is rotatablymounted in suitable bearings 44 and 46. a vei' tegs is provided overtherighthand end ot ,the' housing" 10, as vi ewed;in Figured, andserves to;enclose the rotor 14 within the hoist housingfl The platel 8v s Pr-Q i'with pi ti s d: r al -fit i h h isnadapted to be connected to a suitablesource of air under press ure, The airv supplyi delivered by the fitting50 om uni t s! ht v h itf tz a ir; t passageways (not shown) with. afirst air inletvport -52 and :asecond r kaPs t low hwu hthe iri akpassage-j Wars fiebl v s slatais at or aid i l n altat p pitl. le tiyaPPPlx- L nw ither on the Patented Aug. 12, 1958 3 l ports 52 and 54 inresponse to manual rotation of the rock shaft 42.

The ports 52 and 54 are positioned at opposite sides of and closelyadjacent the rotor-stator seat 22. When an incoming supply of air isadmitted at the inlet port 52, it will be apparent that expansion of thecompressed fluid will perform work against the operating surfaces of thevanes 20, and thereby effect a forward or clockwise rotation of therotor 14, as indicated by the direction arrow 56 in Figure 3. Suchclockwise rotation corresponds to the load up direction of movement ofthe chain 30. When air is alternatively admitted at the inlet port 54,it will be apparent that reverse or counterclockwise rotation of therotor 14 will be effected, as indicated by the direction arrow 58, andsuch rotation corresponds to the load down direction of movement of thechain 30. For purposes of reference, I have designated the longi tudinalaxial center line through the motor shaft 16 by the letter 0. The radialline from the center through the center of the port 52 has beendesignated as station A, and the similar line through the port 54 asstation B. The vertical center line through the top of the motorconstruction has been designated as station C.

It is the particular location of a plurality of primary exhaust ports 60which constitutes the essence of the primary invention. The radial linethrough the center of the primary exhaust ports 60 has been designatedin Figure 3 as station D, and in Figures 4 and 5 as stations D and D",respectively. In Figure 3 the angle COD is equal to about 28, in Figure4 the angle COD is equal to about 13, and in Figure 5, the angle COD" isequal to 0.

The position of the primary exhaust 60 at station D" in Figure 5coincides with station C, and is that of a normally balanced reversiblemotor as conventionally employed by the prior art. Such location is at apoint midway between stations A and B on the opposite side of the stator12. Assuming that the port 52 at station A is employed as an airinlet'and that the port 54 at station-B is employed as a secondaryexhaust, forward rotation of the rotor 14 will be effected when air isdelivered. As the .air acting on the extended vanes efiects forward orclockwise turning of the rotor 14, a certain volume of air will betrapped between adjacent vanes, as indicated at X. Because of thedifierence in the exposed area of the two adjacent vanes bounding thevolume X, there is a force differential exerted by the air pressurewhich tends to continue rotation of the rotor 14 in a clockwisedirection, and as it does so the volume X continuously expands in sizeuntil it reaches the point of exhaust at the midway station C-D". As therotor 14 continues to turn beyond the midway station, a quantity of airat exhaust pressure is trapped between the same pair of adjacent vanesas indicated at Y, and is compressed as the volume continuouslydecreases in size.

The compression volume Y communicates with the secondary exhaust port 54at station B, where the entrapped air is permitted to escape to theatmosphere, thereby completing a pumping cycle for the volume boundedbetween the adjacent vanes. When the expansion volume X travels betweenstations A and C, the air entrapped between the adjacent vanes performswork on the rotor. When the compression volume Y travels betweenstations C and B, the rotor necessarily performs work on the air.Consequently, by shifting the primary exhaust location clockwise fromstation C, it is possible to lengthen that portion of the cycle duringwhich the air does work on the rotor and correspondingly shorten thatportion of the cycle during which the rotor must do work on the air. Inthis manner, it is possible for the motor construction of the presentinvention to provide greater power in its forward direction of rotationthan in its reverse direction of rotation. Such an arrangement may betermed an unbalanced reversible motor.

I'have found that the ratio of forward power to reverse 4 power isdependent upon the positive. angle "of'ofi-set within the range of fromgreater than 0 to 28, with a variation of a few degrees on either sideof the upper 28 limit. In Figure 4 of the drawing, I have illustrated anangular displacement COD of about 13. The angular displacement COD ofabout 28 shown in Figure 3 represents the optimum location of theprimary exhaust. The arrangements of Figures 4 and 5 are intendedprimarily for purposes of illustrating comparative performances. v

- As best seen in Figure 3 of the drawing, the area of communicationbetween the air inlet ports 52 and 54 and the fluid volumes confinedbetween the adjacent rotor vanes is increased by cut-away portions 62and 64. In particular, the cut-away 64 approaches the primary exhaust 60so as to provide a length of internal surface therebetween which isapproximately equal to p the circumferential spacing between the vanesin contact therewith, thereby preventing any substantial compressiontherebetween during forward operation. The size of the cut-away portions62 and 64 shown in Figure 3 will, of course, vary depending upon thenumber of vanes and their circumferential separation, but the particular28 angle of olfset from center for the primary exhaust ports 60 isindependent of the size and spacing of the vanes.

In Figures 6, 7, and 8, I have plotted various performance parameters toillustrate the comparative operation of the arrangements illustrated inFigures 3, 4, and 5,

respectively. The graphs of Figures 6 to 8 include plots of H. P., R. P.M, and air consumption against torque, for both forward and reverserotation of the various motor constructions. These graphs have beenplotted from information obtained by dynamorneter tests on each of threerotor cylinders corresponding to the primary exhaust locations ofFigures 3 to 5. All other motor parts were maintained identical for thedata-obtaining tests. The stator of Figure 3 provides the data of Figure6, and stator of Figure 4 provides the data of Figure 7, and the statorof Figure 5 provides the data of Figure 8. The following information canbe derived from the graphs:

00 0 Parameter Balanced Unbalanced Unbalanced Max. H. P., Forward 1. 09I 1. 25 1. 46 Max. H. P., Reverse 1. 09 .87 .78 Free Speed, Forward 3,800 4, 300 5, Free Speed, Reverse 3, 900 3, 300 3, 150 Air Consumptionat Max. H.

' P P., Forward 42 38 31 It will be seen from the above table that 'ashift of 28 in the ofiset location of the primary exhaust serves toincrease the maximum H. P. for rotation in a forward direction by 0.37,while the corresponding decrease in reverse H. P. is only 0.31. It isalso apparent that the free speed forward for the same two cylinders hasbeen increased by 1350 R. P. M. while the free speed reverse has beendecreased only 750 R. P. M. A further ad vantage will be apparent in theincrease in operating efficiency in a forward direction by comparing thevalue of 42 cu. ft. of air per developed H. P. for the balancedarrangement to only 31cu. ft. of air per developed H. P. for the28offset arrangement.

It will be apparent that by shifting the primary exhaust ports 60off-center to obtain the desired unbalanced power in forward and reverseoperation, there. has been a greater gain in power on the forward "sidethan is lost on the reverse side. I have found that the optimum angle ofdisplacement is that which is suflicient to effect 'a diiferential in H.P. in the forward and reverse direc- 28 offset location provides theapproximately 2:1 differential of 1.87,

Changes may be made in the construction and arrangement of the parts ofmy motor construction without departint from the real spirit and purposeof my invention, and it is my intention to cover by the claims anymodified forms of structure or use of mechanical improvements which maybe reasonably included within their scope.

What I claim as new and desire to obtain by Letters Patent of the UnitedStates is:

1. A reversible fluid motor comprising a stator having a bore defining acontinuously curved internal surface, a rotor eccentrically disposedwithin said bore in bearing contact with said internal surface to definean elongated fluid chamber of synmmetrically increasing cross sectionfrom a minimum area at the ends thereof to a maximum area midwaytherebetween, said stator having a pair of ports communicating with saidchamber at opposite ends thereof closely adjacent said portion of rotorbearing contact, one of said port providing an inlet during forwardrotor rotation and a secondary exhaust during reverse rotor rotation andthe other of said ports providing a secondary exhaust during forwardrotor rotation and an inlet during reverse rotor rotation, and saidstator having on only one side of said maximum chamber area a third portcommunicating with said chamber intermediate said pair of ports andcloser to said other of said ports than to said one of said ports toprovide the only primary exhaust from said chamber.

2. A reversible fluid motor comprising a stator having a bore defining acontinuously curved internal surface, a rotor eccentrically disposedwithin said bore in bearing contact with said internal surface to definean elongated fluid chamber of symmetrically increasing cross sectionfrom a minimum area at the ends thereof to a maximum area midwaytherebetween, said stator having a pair of ports communicating with saidchamber at opposite ends thereof closely adjacent said position of rotorbearing contact, one of said ports providing an inlet during forwardrotor rotation and a secondary exhaust during reverse rotor rotation andthe other of said ports providing a secondary exhaust during forwardrotor rotation and an inlet during reverse rotor rotation, and saidstator having on only one side of said maximum chamber area a third portcommunicating with said chamber intermediate said pair of ports andcloser to said one of said ports than to said other to provide the onlyprimary exhaust from said chamber, the location of said primary exhaustbeing sufficiently unbalanced to one side of said maximum chamber areato effect a diiferential in power in the forward and reverse directionssubstantially equal to 2 to 1.

3. A reversible fluid motor comprising a stator having a bore defining acontinuously curved internal surface, a rotor eccentrically disposedwithin said bore in bearing contact with said internal surface to definean elongated fluid chamber of symmetrically increasing cross sectionfrom a minimum area at the ends thereof to a maximum area midwaytherebetween, said rotor having a plurality of circumferentially spacedvanes radially slidable to etfeet contact with said internal surface anddivide said chamber into adjacent volumes, said stator having a pair ofports communicating with said chamber at opposite ends thereof closelyadjacent said position of rotor hearing contact, one of said portsproviding an inlet during forward rotor rotation and a secondary exhaustduring reverse rotor rotation and the other of said ports providing asecondary exhaust during forward rotor rotation and an inlet duringreverse rotor rotation, and said stator having on only one side of saidmaximum chamber area a third port communicating with said chamberintermediate said pair of ports and closer to said one of said portsthan to said other to provide the only primary exhaust from saidchamber, whereby that portion of said chamber wherein said adjacentvolumes increase in size for expanding fluid from the inlet toward thearea of maximum chamber cross section is of greater length duringforward rotor rotation and of lesser length during reverse rotorrotation than the remaining portion wherein said adjacent volumesdecrease in size for compressing fluid from the area of maximum chambercross section to the secondary exhaust.

4. A reversible fluid motor comprising a stator having a cylindricalbore therein, a rotor of smaller diameter than said bore eccentricallydisposed within said bore in contacting engagement with said stator todefine a hearing seat and a partial annular chamber extending from oneside of said seat to the other, said chamber being of minimumcross-sectional area at opposite ends thereof adjacent said seat andsymmetrically increasing in cross section from each side of said seat toa maximum area directly opposite said seat, said stator having a pair ofports communicating with said chamber at opposite ends thereof closelyadjacent said bearing seat, one of said ports providing an inlet duringforward rotor rotation and a secondary exhaust during reverse rotorrotation and the other of said ports providing a secondary exhaustduring forward rotor rotation and an inlet during reverse rotorrotation, and said stator having on only one side of said maximumchamber area a third port communicating with said chamber adjacent saidarea of maximum cross section and offset from said area of maximum crosssection toward said one of said ports to provide the only primaryexhaust from said chamber.

5. A reversible fluid motor according to claim 4, wherein the offsetlocation of said primary exhaust is at an angle with the axis of saidrotor, formed between radii passing through said area of maximum crosssection and said primary exhaust, of about 28 6. A'reversible motoraccording to claim 4, wherein the ofiset location of said primaryexhaust is at a positive angle with the axis of said rotor, formedbetween radii passing through said area of maximum cross section andsaid primary exhaust, of from greater than 0 up to about 28".

References Cited in the file of this patent UNITED STATES PATENTS

